Okay, went and tried again. Taking a cut depth of about .013" (total of .026"), the 2" measured from the tailstock end are pretty good varying about .00025". Still, when I get to around the last 1" closest to the chuck, it is about a .001" thicker than the other 2 inches
That .013" cut seems like quite a lot to me, I may be wrong but I always believed that when doing this type of check the smallest depth cut is used to minimise any tool spring, work spring etc. which will affect the results, I would have thought that a few tenths of a thou per cut would be used.